US spot Bitcoin ETFs recorded a $450 million net outflow on Sept. 15. It more than erased the previous session’s $159 million inflow, while the six completed sessions since Sept. 8 added up to a net $753 million withdrawal.
The reversal removed the brief demand signal that appeared as the Federal Reserve began its two-day policy meeting. Bitcoin traded near $75,900 at press time, putting the market close to the lower end of the range in Glassnode’s latest weekly snapshot.
ETF net flows measure creations and redemptions across the funds. Investor identities and direct Bitcoin sale execution fall outside the dataset. The useful conclusion is narrower: the ETF reversal arrived alongside broader sell-side pressure.
Spot and perpetual sellers move together
Glassnode’s Week 38 report showed spot cumulative volume delta, a measure of aggressive buying minus aggressive selling, at negative $142 million. That was below its negative $115 million lower statistical band and indicated that sellers were dominating activity on the centralized exchanges in Glassnode’s dataset.
Derivatives sellers were active too. Perpetual cumulative volume delta dropped to negative $605 million, far below its negative $233 million lower band, signaling aggressive selling in perpetual futures.
Leverage remained elevated despite the pressure. Futures open interest, the value of outstanding contracts, eased from $37 billion to $36 billion but remained above its $36 billion upper band. Long-side funding payments, which reflect the recurring transfer between perpetual longs and shorts, rose to $1.4 million while staying within their normal statistical range.
The combination leaves more positioning available to amplify another shock, while normal funding argues against an already extreme long-side imbalance. The Glassnode snapshot also predates Farside’s Sept. 15 ETF row. The adjacent windows support a broad-pressure reading while leaving any causal link between ETF redemptions and exchange selling unresolved.
The Federal Reserve’s policy decision remained pending at the same reporting cutoff. Bitcoin’s first post-decision test was therefore still ahead.
A constructive response would pair price stabilization with improving spot flow while open interest remains orderly. A more convincing bearish second move would combine renewed spot selling with a sharper fall in open interest and a funding reset, evidence that the pressure had spread into forced deleveraging.
Before the decision, the market is best described as vulnerable rather than broken: spot distribution has deepened, derivatives sellers are active, and positioning remains large enough to magnify the next move.